System and method for retrieving network management data from multiple network elements

ABSTRACT

A system for, and method of, retrieving network management data in a network and a network management station incorporating the system or the method. In one embodiment, the system includes: (1) an information querier, associated with a network management station, that develops a query for at least some network management data from a target agent in the network and assigns a path for a response from the target agent that is unique to the target agent and (2) a response receiver, associated with the information querier, that receives, via the path, the response from the target agent containing the at least some the network management data.

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention is directed, in general, to networkmanagement and, more specifically, to a system and method for retrievingnetwork management data from multiple network elements.

BACKGROUND OF THE INVENTION

[0002] Networks have become critical to today's society. Theirimportance is reflected not only in the number of elements (such asservers, clients, hubs, routers and gateways) that are networkedtogether, but also in the varied and complex ways those elements areinterconnected. Undisputably the most widely recognized example of anetwork is the Internet, which is responsible for interconnectingcountless subnets and individual servers and clients.

[0003] As networks have become more complex, network management haslikewise become more automated and standardized. One widely employedarchitecture for automatically managing networks adopts a manager/agenttopology. Network management stations (NMSs) are employed to superviseagents associated with each element in the network that is to bemanaged. Each agent has access to a management information base (MIB)that contains data regarding its associated element. The data include,for example, a unique identity for the element, its operatingcharacteristics and the identities of other elements to which it isconnected. The NMSs query the various agents for the data from theirrespective MIBs. These queries, transported to the agents in packets,conform to a standard protocol called the Simple Network ManagementProtocol, or SNMP.

[0004] The data gathered by the NMSs by means of these messages are usedto model the network in various known ways. Once a model or models aredeveloped, the operation of the network may be optimized and problemsthat may occur in the network from time to time can be diagnosed,localized or resolved.

[0005] For example, in a network having a server, a router, a gatewayand a hub, it is desired to allow an NMS to manage the network. First,the NMS sends a packet containing an SNMP query to, for example, theserver. The server's agent responds with one or more packets containingits MIB response. Then, the NMS sends a packet containing another SNMPquery to, for example, the router. The router' agent responds with oneor more packets containing its MIB response. Then, the NMS sends apacket containing an SNMP query to, for example, the gateway. Thegateway's agent responds with one or more packets containing its MIBresponse. Finally, the NMS sends a packet containing an SNMP query tothe hub. The hub's agent responds with one or more packets containingits MIB response.

[0006] At the risk of being repetitious, the point is made thatgathering MIB information is a serial process. The underlying reason forthis is that requests must be fulfilled one at a time. Otherwise, theMIB information from one element can become confused with the MIBinformation from another element, corrupting the data-gathering process.

[0007] Unfortunately, an individual query/response can take acounterintuitively long time. It has been determined that, on average,query/responses in modern Internet Protocol (IP) networks take about aminute to complete. For the exemplary network above, the query/responsetime is about four minutes.

[0008] One minute per element may not at first glance seem to be aninordinate delay, but modern networks may contain many thousands ofelements. In such networks, delays of many thousands of minutes beforemeaningful network management can be put in place is unacceptable.Accordingly, what is needed in the art is a faster way to retrieve theMIB information necessary for modeling a network so networks can comeunder effective management faster.

SUMMARY OF THE INVENTION

[0009] To address the above-discussed deficiencies of the prior art, thepresent invention provides a system for, and method of, retrievingnetwork management data in a network and a network management stationincorporating the system or the method. In one embodiment, the systemincludes: (1) an information querier, associated with a networkmanagement station, that develops a query for at least some networkmanagement data from a target agent in the network and assigns a pathfor a response from the target agent that is unique to the target agentand (2) a response receiver, associated with the information querier,that receives, via the path, the response from the target agentcontaining the at least some the network management data.

[0010] The present invention therefore introduces the broad concept ofproviding separate paths for responses to network management dataqueries such that the responses do not become commingled and corrupt.

[0011] The conventional MIB information retrieval process described inthe Background of the Invention section above is serial because thepaths used by the NMSs and the agents are standard. More specifically,the IP address of the NMS is the same for all responses. Further,conventional NMSs use port 1961, and conventional agents use port 161.

[0012] The present invention is based on the realization that, while thenumber and commercial source of agents in a network are great(effectively precluding changing port 161), the number of NMSs is small.Thus, the NMSs can be modified to accommodate multiple paths forresponses from agents. This allows multiple paths to be used forparallel retrieval of network management data.

[0013] In one embodiment of the present invention, the informationquerier identifies the path in a source address of a packet bearing thequery. In an alternative embodiment, the information querier identifiesthe path in a port assignment of a packet bearing the query. In anembodiment to be illustrated and described, the path is identified in aport assignment of an IP packet bearing the query. When the target agentresponds, the response is automatically routed according to the sourceaddress and port assignment. An alternative embodiment will also bedisclosed a unique source address is employed to define each path.

[0014] In one embodiment of the present invention, the response receivercomprises a buffer that receives and contains the response. The responsereceiver reads the response from the buffer following a predeterminedperiod of time. Alternatively, the response receiver can count responsesand read the responses from the buffer based on the count.Alternatively, the response receiver can handle responses one at a time.

[0015] In one embodiment of the present invention, the response is afirst response and the information querier develops a second query forat least some network management data from a second target agent in thenetwork and assigns a second path for a second response from the secondtarget agent that is unique to the second target agent before theresponse receiver receives the first response. The present invention canoffer a substantial advantage in allowing network management dataqueries and responses to be performed in parallel, allowing the processof gathering network management data to be performed substantiallyfaster.

[0016] In one embodiment of the present invention, the query and theresponse conform to SNMP, and the network is an IP network.

[0017] The foregoing has outlined, rather broadly, preferred andalternative features of the present invention so that those skilled inthe art may better understand the detailed description of the inventionthat follows. Additional features of the invention will be describedhereinafter that form the subject of the claims of the invention. Thoseskilled in the art should appreciate that they can readily use thedisclosed conception and specific embodiment as a basis for designing ormodifying other structures for carrying out the same purposes of thepresent invention. Those skilled in the art should also realize thatsuch equivalent constructions do not depart from the spirit and scope ofthe invention in its broadest form.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] For a more complete understanding of the present invention,reference is now made to the following descriptions taken in conjunctionwith the accompanying drawings, in which:

[0019]FIG. 1 illustrates an NMS incorporating a system for retrievingnetwork management data constructed according to the principles of thepresent invention and a network having elements from which networkmanagement data are to be retrieved;

[0020]FIG. 2 illustrates a diagram in an Unreliable Delivery Protocol(UDP)/IP packet, including a source address field and a source port thatalternative embodiments of the present invention can employ; and

[0021]FIG. 3 illustrates a method of retrieving network management datacarried out according to the principles of the present invention.

DETAILED DESCRIPTION

[0022] Referring initially to FIG. 1, illustrated is an NMSincorporating a system for retrieving network management dataconstructed according to the principles of the present invention. FIG. 1also illustrates a network coupled to the having elements from whichnetwork management data are to be retrieved. The network, generallydesignated 110, is illustrated as including a server 110, a router 120,a gateway 130, a hub 140 and a client 150. Those skilled in the artunderstand, however, that a real-world network would commonly have manyof each of these representative network elements.

[0023] Each of the server 110, the router 120, the gateway 130 and thehub 140 has an associated SNMP agent (agents 111, 121, 131, 141,respectively) that allows its respective element to be managed by anNMS.

[0024] The agents 111, 121, 131, 141 are conventional. That is, theagents 111, 121, 131, 141 monitor port number 161 for packets containingSNMP messages (including “get” messages that function as queries). Theagents 111, 121, 131, 141 conventionally react to the SNMP messages byreading from or writing to associated MIB memory (MIB memory 112, 122,132, 142) that contains network management data regarding the associatedelement. Standards with which those skilled in the pertinent art arefamiliar govern the content, structure and retrieval of the networkmanagement data.

[0025] In the case of SNMP “get” messages, the agents 111, 121, 131, 141generate responses containing at least some of the network managementdata and cause those responses to be encapsulated into a packet andreturned to the same network address from which the original packetbearing the SNMP “get” message was sent. Thus, the agents 111, 121, 131,141 copy a source address field in the packet containing the SNMP “get”message to a destination address field in the packet containing theresponse.

[0026] As has been described above, conventional NMSs have only usedport number 1961 as the source address in packets they originate. Thus,the destination address field generated by the agents 111, 121, 131, 141has heretofore referred only to port number 1961. The embodiment of FIG.1 is not limited to port number 1961.

[0027] The illustrated system, constructed according to the principlesof the present invention, is generally referenced 170 and allows thisartificial constraint to be lifted to significant advantage. The system170 is illustrated as being incorporated into an NMS 160. In addition tothe system 170, the NMS 160 includes a network interface 161 for linkingthe NMS 160 to the network 100. The NMS 160 also includes networkcontrol circuitry 162. The network control circuitry controls theelements of the network 100 (e.g., the server 110, the router 120, thegateway 130 and the hub 140) based at least in part on the networkmanagement data that the system 170 retrieves from the elements.

[0028] The system 170 is illustrated as including an information querier171. The information querier 171 develops a query for at least somenetwork management data from a target agent (e.g., the agents 111, 121,131, 141) in the network 100 and assigns a path for a response from thetarget agent that is unique to the target agent. In the case of theillustrated embodiment, the information querier 171 assigns a port tothe source address of the IP packet bearing the SNMP “get” message thatis unique to each agent 111, 121, 131, 141. In making this assignment,the information querier 171 advantageously avoids reserved ports.

[0029] For example, the information querier 171 may assign port number111 to the agent 111, port number 121 to the agent 121, port number 131to the agent 131 and port number 141 to the agent 141. Those skilled inthe art should understand, however, that the port assignment need haveno relationship whatsoever to the identity of the target agent and thatthe ports need not be consecutive or conform to any assignment patternwhatsoever.

[0030] Having assigned the ports to their respective target agents (e.g., the agents 111, 121, 131, 141), the information querier thencauses packets that bear the SNMP “get” message to be generated andtransmitted via the network interface 161 in succession, without havingto wait for responses from any of the target agents (e.g., the agents111, 121, 131, 141).

[0031] Each of the target agents ( e.g., the agents 111, 121, 131, 141)receives its respective “get” message, queries its respective MIBmemories (the MIB memory 112, 122, 132, 142) to retrieve the appropriateMIB information and formulates its respective response in a conventionalmanner. When the various responses are “packetized” for the return tripto the system 170, the destination address of the packet(s) includes theunique ports that the information querier 171 earlier assigned. This isunlike the prior art, where one return path (e.g., port number 1961) wasused for all responses. Thus, the packets bearing the responses returnto the system 170 along separate and unique paths and, in theillustrated embodiment, concurrently without being commingled andbecoming corrupt.

[0032] The system 170 is further illustrated as including a responsereceiver 172. The response receiver 172 receives, via the paths that theinformation querier 171 assigned as detailed above, the responses fromthe various target agents e(.g., the agents 111, 121, 131, 141)containing the at least some the network management data that ostensiblyfulfills the queries.

[0033] Assuming that responses take one minute apiece, the agents 111,121, 131, 141 can be queried and return their respective responses inone minute (neglecting network transport times), instead of the fourminutes the prior art process required. Extrapolating this to a largenetwork having, say, 3600 managed elements, the various responses canstill be returned in one minute instead of the 60 hours that the priorart process would have required. Of course, those skilled in the artwill recognize that some responses may be faster or slower than oneminute and that certain agents may have to be re-queried. However, asignificant time savings can still be realized by applying theprinciples of the present invention.

[0034] Particular to the embodiment illustrated in FIG. 1 is a buffer173 that receives and contains the responses. The response receiver 172reads the response from the buffer 173 following a predetermined periodof time. Alternatively, the response receiver 172 can count responsesand read the responses from the buffer 173 based on the count.Alternatively, the response receiver 172 can handle responses one at atime.

[0035] In an alternative embodiment, the system 170 assigns uniquesource IP addresses to each query. The various responses from the agentsuse the respective source IP addresses as return paths. Though theresponses all arrive at the response receiver 172, they took uniquepaths getting there. This embodiment is especially useful if theunderlying operating system limits the number of ports that can beallocated to a single process or thread.

[0036] Turning now to FIG. 2, illustrated is a diagram of a UDP/IPpacket, generally designated 200. The UDP/IP packet 200 includes asource port field 210 in the UDP header portion of the UDP/IP packet 200that the illustrated embodiment of the present invention employs. FIG. 2also illustrates a source address field 220 in the IP header portion ofthe UDP/IP packet 200. As stated above, an alternative embodiment of thepresent invention can use the source address field to define uniquepaths for responses.

[0037] Those skilled in the pertinent art are familiar with thestructure of the UDP/IP packet 200 and how the source port field 210 andsource address field 220 are formatted, generated and used to route thepacket through an IP network. Those skilled in the art should alsorealize that a Transmission Control Protocol (TCP)/IP packet may also beemployed to bear an SNMP “get” message.

[0038] Turning now to FIG. 3, illustrated is a method, generallydesignated 300, of retrieving network management data carried outaccording to the principles of the present invention. The method 300begins in a start step 310, when it is determined that networkmanagement data should be retrieved from elements in the network.

[0039] The method proceeds to a step 320, in which queries (e.g., SNMP“get” messages) are developed for the elements. Next, in a step 330, aunique path is assigned to each query for its respective response (e.g.,a unique port or source address). Then, in a step 340, each query is“packetized” in a packet that indicates the unique path. Then, thequeries are transmitted in succession into the network destined for theSNMP target agents associated with their respective elements.

[0040] It is assumed that the various target agents then begin toretrieve their respective network management data and generate“packetized” responses along their unique return paths. Though theresponses may travel concurrently over the network, they do notcommingle by virtue of their unique paths.

[0041] Next, in a step 350, the various responses are received into abuffer. In a step 360, the responses are read out from the bufferfollowing some period of time by which it is assumed that most if notall of the responses will have been received. Of course, otherprocedures for receiving the responses fall within the broad scope ofthe present invention.

[0042] Finally, in a step 370, the network management data thuscollected is arranged and employed to construct one or more models ofthe network employable to optimize the operation of the network ordiagnose, localize or resolve problems that may occur in the networkfrom time to time. The method 300 ends in an end step 380.

[0043] As a parting note, it should be understood that the NMS may notchoose to query all of the elements of the network at once. Instead, itmay choose to query a subset of the elements, perhaps a few hundred orfew thousand at a time. In such case, once the responses are receivedvia their unique paths, those unique paths become available for reusevis-a-vis future queries.

[0044] Although the above-described and illustrated system, method andNMS operate with an IP Ethernet network and employ SNMS to retrievenetwork management data and manage the network, those skilled in thepertinent art will readily understand that the principles of the presentinvention are applicable to protocols other than IP and SNMS andnetworks other than Ethernet. Also, although one embodiment of thepresent invention has been described in detail, those skilled in the artshould understand that they can make various other changes,substitutions and alterations herein without departing from the spiritand scope of the invention in its broadest form.

What is claimed is:
 1. A system for retrieving network management datain a network, comprising: an information querier, associated with anetwork management station, that transmits a query for at least somenetwork management data from a target agent in said network thatincludes a path for a response from said target agent that is unique tosaid target agent; and a response receiver, associated with saidinformation querier, that receives, via said path, said response fromsaid target agent containing said at least some said network managementdata.
 2. The system as recited in claim 1 wherein said informationquerier identifies said path in a source address of a packet bearingsaid query.
 3. The system as recited in claim 1 wherein said informationquerier identifies said path in a port assignment of a packet bearingsaid query.
 4. The system as recited in claim 1 wherein said responsereceiver comprises a buffer that receives and contains said response,said response receiver reading said response from said buffer followinga predetermined period of time.
 5. The system as recited in claim 1wherein said response is a first response and said information queriertransmits a second query for at least some network management data froma second target agent in said network that includes a second path for asecond response from said second target agent that is unique to saidsecond target agent before said response receiver receives said firstresponse.
 6. The system as recited in claim 1 wherein said query andsaid response conform to a Simple Network Management Protocol.
 7. Thesystem as recited in claim 1 wherein said network is an InternetProtocol network.
 8. A method of retrieving network management data in anetwork, comprising: transmitting a query for at least some networkmanagement data from a target agent in said network that includes a pathfor a response from said target agent that is unique to said targetagent; and receiving said response from said target agent containingsaid at least some said network management data.
 9. The method asrecited in claim 8 further comprising identifying said path in a sourceaddress of a packet bearing said query.
 10. The method as recited inclaim 8 further comprising identifying said path in a port assignment ofa packet bearing said query.
 11. The method as recited in claim 8wherein said receiving comprises receiving said response from saidtarget agent containing said at least some said network management datainto a buffer and said method further comprises reading said responsefrom said buffer following a predetermined period of time.
 12. Themethod as recited in claim 8 wherein said response is a first response,said method further comprising: transmitting a second query for at leastsome network management data from a second target agent in said networkthat includes a second path for a second response from said secondtarget agent that is unique to said second target agent before saidresponse receiver receives said first response.
 13. The method asrecited in claim 8 wherein said query and said response conform to aSimple Network Management Protocol.
 14. The method as recited in claim 8wherein said network is an Internet Protocol network.
 15. A networkmanagement station, comprising: a network interface for linking saidnetwork management station to elements in an Ethernet network to becontrolled; a network control circuitry, coupled to said networkinterface, for controlling said elements based at least in part onnetwork management data retrieved from said elements; and a system forretrieving said network management data from said elements, including:an information querier that develops a Simple Network ManagementProtocol query for at least some network management data from a targetagent associated with one of said elements and assigns a path for aresponse from said target agent that is unique to said target agent, aresponse receiver, associated with said information querier, thatreceives, via said path, said response from said target agent containingsaid at least some said network management data.
 16. The networkmanagement station as recited in claim 15 wherein said informationquerier identifies said path in a source address of an Internet Protocolpacket bearing said query.
 17. The network management station as recitedin claim 15 wherein said information querier identifies said path in aport assignment in an Internet Protocol packet bearing said query. 18.The network management station as recited in claim 15 wherein saidresponse receiver comprises a buffer that receives and contains saidresponse, said response receiver reading said response from said bufferfollowing a predetermined period of time.
 19. The network managementstation as recited in claim 15 wherein said response is a first responseand said information querier develops a second query for at least somenetwork management data from a second target agent in said network andassigns a second path for a second response from said second targetagent that is unique to said second target agent before said responsereceiver receives said first response.